bpo-38971: Open file in codecs.open() closes if exception raised. (GH-17666)

Open issue in the BPO indicated a desire to make the implementation of
codecs.open() at parity with io.open(), which implements a try/except to
assure file stream gets closed before an exception is raised.

1 files changed, 9 insertions, 0 deletions

diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 8d9cb90890..dcdd574bc7 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -1154,6 +1154,7 @@ class UTF8SigTest(UTF8Test, unittest.TestCase):
             got = ostream.getvalue()
             self.assertEqual(got, unistring)
 
+
 class EscapeDecodeTest(unittest.TestCase):
     def test_empty(self):
         self.assertEqual(codecs.escape_decode(b""), (b"", 0))
@@ -1725,6 +1726,14 @@ class CodecsModuleTest(unittest.TestCase):
             self.assertRaises(UnicodeError,
                 codecs.decode, b'abc', 'undefined', errors)
 
+    def test_file_closes_if_lookup_error_raised(self):
+        mock_open = mock.mock_open()
+        with mock.patch('builtins.open', mock_open) as file:
+            with self.assertRaises(LookupError):
+                codecs.open(support.TESTFN, 'wt', 'invalid-encoding')
+
+            file().close.assert_called()
+
 
 class StreamReaderTest(unittest.TestCase):